I haven't used TrackerJacker, but the sheet has never been compatible with CreatureGen. I used CreatureGen extensively, and I could never, ever, click on the character sheet tab, or it would screw up everything and i'd have to re-run the import. The way it messes up with CreatureGen: a few items have the same attribute names as CreatureGen uses. If I clicked on the character sheet, it would reset the values to something else, this would break some attacks and initiative resulting in adding +0 Part of the reason I worked so hard on the monster compendium import was so i wouldn't need creaturegen anymore. (well we still don't have auto-created abilities/token macros , bu at least have menus) I wanted to try TrackerJacker but since Ken is not supporting his stuff and it's getting older and older I'm afraid to get dependent on it. but yeah, keeping a copy to freeze it, then maybe using a copy to upgrade and see how it works, is smart. In a few days a notice will go on the top of the page in the announcements advising GMs to backup their campaigns. I am all nervous after seeing the responses to the DnD 5 sheet :)